The six-year-old burst on to the scene at the end of last season, beating some useful rivals hollow at the Punchestown Festival.
Un De Sceaux has looked extremely impressive in two races this year, but his critics point to the fact that he only defeated two runners at Thurles and at Navan.
He will only face three rivals on Sunday – stable companion Midnight Game, Chicago and The Four Elms.
While the Champion Hurdle would represent a huge step up in class, Mullins is content to keep picking up races along the way.
“Running on ground that is going to be this heavy is always a worry but he appears to handle it well,” said the County Carlow handler.
“If he runs to anything like his previous form then you’d think he could win.
“I’m not worried at all that if he runs at Cheltenham he will not have faced a tough test, I’m quite happy building him up step by step.
“I’m quite happy building up gradually and keeping him happy.”
Meanwhile Mullins’ Turban gets the chance to follow up his hugely impressive Fairyhouse display when he reappears in the Red Mills Chase.
The seven-year-old made a mockery of his handicap mark in the Dan Moore Chase, pulling six lengths clear of Competitive Edge.
Mullins feels if he can reproduce anything like that display then he will be hard to beat, especially as he gets weight off some of his rivals.
“Turban was very impressive at Fairyhouse last time out and if he runs to his new rating (151) then he should have a good chance as he looks nicely in,” said Mullins.
“However, this is the first time he’s run off anything like this rating so we’ve yet to see if he’s up to it or not.
“If he can match his last performance then you would expect him to prove hard to beat, especially in these conditions as he handles them very well indeed.”
An interesting sub-plot to the race is that the former Mullins-trained Aupcharlie makes his debut for Henry de Bromhead.
Also declared are Tom Taaffe’s Argocat, Mouse Morris’ Rathlin and Tony Martin’s Grade One-winning chaser Bog Warrior, not seen since picking up an injury when fifth in the World Hurdle. He is also declared in the Boyne Hurdle at Navan on Sunday.
Martin is just pleased to be able to get Bog Warrior back on track after picking up a serious injury at Cheltenham. “The intention is to run at Gowran, we’ve only put him in at Navan in case the meeting is off,” said Martin.
“It’s a relief that we’ve got him back this season, when he was hobbling out of the parade ring at Cheltenham it didn’t look good.
“It was very unfortunate what happened, Bryan Cooper said he felt he would definitely have been involved in the finish of the World Hurdle but he felt him go wrong at the back of the second-last, who knows what would have happened.
“It’s hard to say if he’s as good as ever, it’s very rare for them to come back from injuries as bad as that and be every bit as good – I’d love it if he was.”